Sky's DLM keeps setting an unstable 3db profile

After my resent problems a few weeks ago regarding the router freezing,now solved by using my old Be* router,,The DLM has kicked in again on my line.It is a nightmare as each time it kicks in it sets my line at 3db,,which causes disconnections,if I wait till it see's the disconnections it will kick in again,and just set at 3db's again.

I have rang sky 3 times already since November and each time after going through 24 hr line testing etc,a 2nd line tech support will ring and re-profile my line to 6-10db which makes it stable for weeks on end.

Until about the 6wk mark when DLM decides to mess it up.

The tech lads I've spoken to over the time say my line is great but the DLM on some lines is just to aggressive and sets the upload at 2.5mb resulting in 3db,,when they adjust the line to 1.1mb upload the SNR goes to around 9-10db.

Each time they do a manual profile they freeze the DLM for a week.But maintime they cannot turn it off all together.

So does anyone know if the DLM can be switched off by sky permanently,as it is a real pain to ring them and keep going through the motions of testing-then trying to sell me fibre-then eventually 2nd line tech will ring.

Just to add,DLM has kicked in again on my line that has been connected for about 4-5 weeks.no disconnection no noise on the line nothing.

And my next question is which ISP doesn't use this DLM,,Does plusnet use it?

Sorry for the rant,just really annoying me having to ring sky to do a manual adjustment on the line.

here are my stats,,it disconnected for its testing about 2am last night.
Uptime: 0 days, 18:59:48

DSL Type: ITU-T G.992.5

Bandwidth (Up/Down) [kbps/kbps]: 1.256 / 12.286

Data Transferred (Sent/Received) [GB/GB]: 1,47 / 2,43

Output Power (Up/Down) [dBm]: 12,1 / 18,9

Line Attenuation (Up/Down) [dB]: 17,3 / 34,0

SN Margin (Up/Down) [dB]: 4,8 / 2,6

System Vendor ID (Local/Remote): TMMB / ----

Chipset Vendor ID (Local/Remote): BDCM / BDCM

Loss of Framing (Local/Remote): 17 / 0

Loss of Signal (Local/Remote): 2 / 0

Loss of Power (Local/Remote): 0 / 0

Loss of Link (Remote): -

Error Seconds (Local/Remote): 1.593 / 18

FEC Errors (Up/Down): 0 / 980.684

CRC Errors (Up/Down): 172 / 1.977

HEC Errors (Up/Down): 67 / 0

Or you could try turning your router off and on once a week or so just to keep the DLM unhappy.

I think the issue may be the BE router.

I say this because the BE router in my experience doesn't show a flappy noise margin where other routers do.

IE on my second line the BE router would always shows a noise margin fixed at 3db whereas the Sky Hub on the same line showed the noise margin ranging between 1db and 4db.

DLM on the Sky Hub sees the issue, sets the line to 6db noise margin.

With the BE router it keeps it at 3db.

I would personally get hold of a Sky Hub. For the record the Sky Hub does not freeze, mines had uptimes over 6 months, if yours does then it's faulty.

If that doesn't resolve things, Skys DLM is often stricter than the competition, so if you are seeing 3db with Sky you will probably see it elsewhere too.

How often are these disconnections with a 3db noise margin? I find it odd that DLM isn't noticing them during line testing, hence why you get the 3db margin.

Other ISPs, I believe virtually all have some kind of line management / DLM.

I don't think it's the Be router as I've only just gone back to using it around 4-5weeks ago due to the sky one freezing,, it's been setting the line at 3db with the SR102,,in fact 2 as I got a replacement.

What will happen is the DLM starts for no reason, during a solid connection time. Is will drop the connection at around 1-2am each night for about 3 nights. During this testing phase the line doesn't drop, even at 2.6db at night.

Then it will complete, I'll see this in my sky account, never take more than 3-4 days,, as soon as it completes, is starts disconnecting at night when the SNR drops from about 9pm,1-3 times, after about 3-6 days DLM starts again as it sees disconnections I assume,, during this time again it only disconnects at the specific times that DLM does, DLM can complete in just 3 days again,, as it doesn't disconnect during the DLM period, it keeps it at 3db.

Sky told me it's an issue they see on some accounts, no often, but, the tech guys new about it (whatever 'it' is) blamed the 2.5mb upload glitch (there words) , they said it's trying to connect at nearest the 2.5mb upload as it can resulting in low SNR.. Even though sky only do 1.2mb upload Max anyway., they said it's a glitch, as soon as they put my connection to around 1.1mb upload, I see the SNR at around 9ish dB. Perfect then, till next time.

They tell me everytime I ring they can see disconnections and lots of errors? Then when they reprofile they ring me back about every 2 days for a week, reporting no errors, or very few.

Told me I will have this issue again and again, but they will not switch DLM off permanently, only for about a week to let it settle after they reprofile the line.

Maybe I should unplug the router as suggested, but during DLM time?

Never had this with Be, it was just on 6db that's it. I'd love that again.

There's no reason why your line wouldn't drop out during DLM testing. That's what I don't understand. It has the same likelihood during DLM as normally.

Can you get fibre where you are? It is likely to solve the issues as you won't see such a low noise margin on fibre normally.

2.5 upload is bull. That is annex m and should only be used in limited cases certainly is never used on standard sky. If flipping you between adsl2+ and annex m router should show a standard change too

Sr102 freezing is probably it behaving due to same problem

Talktalk and bt wholesale dlm can be pegged but can be a pain to do

Sky sets 2.5mb as the maximum upstream as they where supposed to be implementing Annex M onto the LLU network around the UK...

However AFAIK it isn't currently activated on any lines or exchange equipment.

Sounds like a hardware issue, might be worth getting Sky to send another Sky Hub or source another router or modem that is known to work well on long lines (Though that can be tricky)

The annex M was afaik only meant to have been an option for old Be customers, if you can find 'official' and not internet rumour machine saying the whole Sky network was going to move to Annex M which only ever really benefited those with lines syncing above 16 Mbps then happy to change position.

Easy to tell if Annex M as modem reports the different standard.

It was a Sky representative that told me about the Annex M implementation and that it would be based on DLM and also Sync speed & would be first rolled out to ExBe users in the Pro package which they planned to make public later on...

Not sure but I think they made the Pro ADSL public a while back but you have to call for it to be added after a standard unlimited service is activated.

Will a Sky hub report the difference though... and upstream speeds with with Annex M might not get much higher than Annex A, In my past experience when using O2 LLU I only saw a 150kbps improvement which pushed my 1000kbps to 1150 on a 2.5Km line.

Is this annex M?

Link Information

Uptime: 0 days, 9:05:23

DSL Type: ITU-T G.992.5

Bandwidth (Up/Down) [kbps/kbps]: 1.274 / 11.198